I service my housings/strobes as follows:
1° Main housing o-ring: work on most housings on compression and need no grease but have to be clean and checked for salt build-up or other dirt
2° Port o-ring: most of them have to be twisted to lock, so it is necessary to lubricate them to avoid that they get stuck and/or twisted
3° knobs and dials o-ring: they work on moving stems so they need to be lubricated, i grease them from the outside applying tiny amounts of grease to the stem
I NOT recommend them to be serviced as they may get the shape of the stem and mounting them differently may lead to leaks
replace them only with new o-rings
Lubrificating o-rings: use only a small amount of grease and check that it is the manufacturer recommended grease type,
use just enough to make your fingertips slippery and pass the o-ring trough your fingertips that it get shiny but no excess grease on it
Never use any hard pick to pull o-rings out of the groove, pinch them gentle together with your fingers to form a loop and remove them
being very careful not to over stretch or damage them.
Clean the groove with a lint free towel before you slip/push the o-ring back in place and respect the shape of the o-ring he may acquired.
I wash my housings after the dive with lots of running water, move all knobs and dials several times and dry it after with a towel and dry carefully the port lens
to avoid water spots on the glass/acrylic material.
I let the housing to dry after i moved all knobs and dials to squeeze as much of the the water out and let it dry with the knobs downwards on a table outside in the shade.
Frequent unscrewing of the SS screws may help with galvanic corrosion, i use PTFE Tape (teflon pipe dope) for all screws to isolate the ss screws from the aluminium housing as this will
greatly reduce galvanic corrosion. Be warned that grease is not a good solution as grease build-up inside the treaded hole may "clog" it and as grease is "uncompressable" it can crack the housing
while applying too much force.
Chris